1. Field of the Invention
This invention relates generally to a magnetic shield member, and more particularly, to a combined magnetic shield member and pressure pad for a magnetic reader.
2. Description of the Background
Face-to-face retail sales transactions take place at a point of sale (“POS”) or what is commonly referred to as a checkout line or a counter. In this case, a customer typically purchases goods by either cash, check, charge or debit card.
To effectuate a sales transaction, many retailers presently use a POS system to facilitate and provide a record of the sales transactions. Such a POS system may include a scanner for reading coded product price, a terminal for manual entry of transaction information and storage of currency and a printer which may be used to produce a documentary record or journal for the business and a printed receipt for the customer.
In addition, the POS system may include a check processing system to facilitate the sales transaction when a check is used for payment. The check processing system includes a magnetic ink character recognition (“MICR”) reader for reading magnetic information stored in magnetic ink printed on a front side of checks or other documents. However, in order to generate a strong magnetic signal which is required to accurately read the magnetic information from the checks or other documents, the checks and other documents must be kept in close contact with the MICR reader. Therefore, a pressure pad which applies a force onto a backside of the checks or other documents has been previously developed in order to keep the checks or other documents in close contact with the MICR reader.
However, check processing systems including the MICR reader can be affected by magnetic interference generated from external and internal sources. That is, external sources, such as display devices and scanners, and internal sources, such as paper feed motors, print heads and solenoids, generate magnetic fields which result in magnetic interference relative to the magnetic information stored within the magnetic ink portion of the checks or other documents. The magnetic interference prevents the MICR reader from accurately reading the magnetic information stored on the checks or other documents. Nonetheless, in order produce a low-cost and high throughput printer, the MICR reader must be positioned as close as possible to other components within the printer, including the paper feed motors and the print head.
One of the methods used to overcome this problem with magnetic interference has been to surround the MICR reader and pressure pad with a high permeability shielding material, including a nickel alloy such as Mu-Metal™ or Permalloy™, to thereby shield the MICR reader from magnetic interference. However, this method significantly increases a manufacturing cost of the printer since the high permeability shielding material is expensive and a large volume thereof is required in order to surround the MICR reader and pressure pad. In addition, due to the large amount of material volume and the proximity to other components within the printer, the high permeability shielding material can cause additional problems, such as overheating.
Therefore, in order to reduce the effect of magnetic interference on the MICR reader, minimize an overheating of the printer and reduce a manufacturing cost of the printer, a magnetic interference shield which uses a minimum amount of material volume is desirable.